The end of each world features a Boss fight. Each boss requires six hits to be defeated. You must hit them three times to unlock the first checkpoint. They will then summon some enemies that you must fight to reach the second checkpoint. You then have to hit the boss three more times to defeat it. Usually, these enemies can be hit when their faces are yellow and not red. Also, if they are on the ground sideways and are yellow, you can simply roll into them with some speed to hit them; no jumping is required. The final Boss last phase may be difficult. Wait until the incoming enemies have been triggered to explode, then start rolling in their direction, jumping over them about halfway through. They should continue onward and hit the Boss themselves.
Damaging enemies
Hit enemies from a vertical angle and not a horizontal one to damage them and not yourself. You must take into account your approach toward your target. When targeting bouncing enemies, hit them while they are moving upward, and not on the ground. Explosive enemies are dangerous, as they do massive damage and can home in on you. Try to hit them on the head to freeze them in place, then get away.
Gold medals
To earn a gold medal, collect all the stars that appear in that level and defeat every enemy. With the enemies that respawn, you only have to defeat them during their first appearance.
Momentum
When faced with a large gap, you must get a rolling start. Continue to hold in the direction that you are travelling to get the maximum distance from your jump. This technique is also required by a few puzzles, For example, if you need to start rolling an object so that it hits a switch while travel to the gate the switch opens. Lightly touch the object on a flat surface and it will keep rolling forward while you can move to your destination.
Sad indicator
If you are in a state where the currently level cannot be completed, Red Ball will frown. This usually happens after you have lost an item that was necessary to complete the level.
